England’s concrete crisis could extend to hospitals and courts, experts say
England’s concrete crisis could extend to hospitals and courts, experts say
Labour demands urgent audit of government’s handling of longstanding concerns about Raac
TLDR you limey bastards built school roofs out of a material that was advertised as with a 30 year life span, and here we are 40 years later and its surprised pikachu faces all around.
advertised as with a 30 year life span,
It's not clear to me from the article whether it was expected to only last 30 years at the time, or whether it was subsequently revised down in some way.
I mean, my guess is that many building materials may only guarantee some number of years, but it may be the norm for them to last longer. I assume that businesses selling stone do not rate, say, masonry for hundreds of years, though it clearly can last that long.
The article has:
Raac, a lightweight building material, was commonly used in panel-form in public building construction from the 1950s to mid-1990s. It is estimated to have a lifespan of 30 years, and many structures have now passed that age.
EDIT: Yeah. From another article, it sounds like at the time it was built, it was not realized that the material would last only 30 years:
During the post-war building boom of the 1950s, 60s and 70s, reinforced aerated autoclaved concrete (RAAC) was something of a wonder material.
In the 1990s, when the material was still being used, structural engineers discovered that the strength of RAAC wasn't standing the test of time.
The porous, sponge-like concrete - especially when used on roofs - could easily absorb moisture, weakening the material and also corroding steel reinforcement within.
As it weakened, it sagged, leading to water pooling on roofs, exacerbating the problem.
RAAC made in the 1950s was at risk of failure by the 1980s, the report concluded.
About 30 years ago, it became known that the lifespan of RAAC in many public buildings, including hospitals and schools was no greater than 30 years.
More like getting on for 60 years in some cases.
How the hell have we messed up concrete? The Romans had concrete that is still with us today.
The difference between a Victorian bridge and a modern one, is that the Victorian one was built to definitely stay up, while the modern one is built to just stand up.
Because just is all you need, when you can calculate so much of the design, and know the service life.
What's happened here, is a lot of the buildings were built with a service life that was within the bounds of aerated concrete. The buildings were supposed to be replaced by now, but budget constraints have meant that they've been pushed beyond their service life.
Or in analogous terms: You have to stay in a house for a week, you buy some disposable plates and cutlery.
2 months later, you're still there, and all the plastic forks have broken.Couple that with the bidding process for infrastructure contracts, and anything built in the last 40-50 years by government contract is likely to be falling apart before too long.
and know the service life.
According to other articles that I linked to in this thread, the problem was only discovered in the 1990s, that the stuff had a relatively short lifetime.
To be fair, the Romans also had a lot of concrete that is not with us today, there's a bit of survivorship bias going on here.
Sure, but Roman concrete was also actually really good due to the ingredients used. They had self-healing concrete millennia before we came up with the idea.
A fair critique is the Romans built their shit to last and didn't have advanced computers to calculate loads to just ~10% of failure, like we do now. We'll use cheaper, local materials if it's good enough and make sure the building stands for maybe a century. The Romans shipped ash and concrete ingredients halfway across Europe to make sure they were using the good stuff.
Roman concrete was more durable than most modern concrete, but was much, much weaker. It also relied on volcanic ash, which isn't as readily available as the ingredients for portland cement. Being able to have larger freestanding spans and lower construction costs due to reinforcement is usually worth a much shorter design lifetime.
The reinforced aerated autoclaved concrete was clearly a mistake, trying to make a concrete foam to reduce weight meant that more water could get to the rebar and cause corrosion much more quickly than in normal reinforced concrete.
This is the best summary I could come up with:
The Labour MP Meg Hillier, who chairs the public accounts committee, said Raac was “the tip of the iceberg” of maintenance issues within the school estate.
She questioned why the situation had been “left to deteriorate for so long”, telling Times Radio: “In both schools and hospitals, there hasn’t been enough money going into buildings and equipment.”
Matthew Byatt, the head of the Institution of Structural Engineers, said any high-rise buildings with flat roofs constructed between the late 1960s and early 1990s could contain Raac.
The DfE’s U-turn – which means all buildings or areas with Raac must close – follows instances where the material collapsed despite it being considered low risk.
Speaking to BBC Radio 4’s Today programme on Friday, the schools minister, Nick Gibb, said the department had discovered a “number of instances” over the summer.
Sarah Skinner, the chief executive of Penrose Learning Trust, which has three affected schools, told the Today programme on Saturday that the notification on Thursday seemed “very late in the day”.
The original article contains 812 words, the summary contains 169 words. Saved 79%. I'm a bot and I'm open source!
Anyone aware of the RAAC collapses the article refers to?
Sounds like one was not identified and collapsed in 2017. Another was Singlewell Primary School in Kent in 2018.
When was RAAC flagged as a danger?
The lightweight concrete, which is a “porous” material, has long been recognised as having “limited durability”, according to the LGA. The Government has been aware of public sector buildings constructed with the material since 1994.
2017
The Standing Committee on Structural Safety was asked to investigate the suitability of the material after a school roof collapsed, although it is not clear which school this was.
2018
Another roof collapsed at a Singlewell Primary School in Kent. It happened above the school staff room, also damaging toilets, ICT equipment and an administration area. The collapse prompted Kent Council to write to other local authorities warning them to check for RAAC in their schools.
2019
A structural engineer investigating on behalf of SCOSS began to “frequently” encounter RAAC planks that weren’t fit for purpose and warned all those installed before 1980 should be replaced.
Never heard of it until this moment
I’m sure there’s some nice big contracts going out to construction firms that just happen to donate to certain MP’s
The one I haven't seen mentioned, but I would expect to be affeceted are universities. Lots of concrete blocks going up in the late 60s
Parts of Aberdeen uni were/are closed because of the stuff
Brutalism was also a thing in that period, and that had a lot of externally-visible concrete. But I don't know if that specifically was linked to this particular RAAC stuff.
https://en.wikipedia.org/wiki/Brutalist_architecture
Brutalist architecture is an architectural style that emerged during the 1950s in the United Kingdom, among the reconstruction projects of the post-war era.[1][2][3] Brutalist buildings are characterised by minimalist constructions that showcase the bare building materials and structural elements over decorative design.[4][5] The style commonly makes use of exposed, unpainted concrete or brick, angular geometric shapes and a predominantly monochrome colour palette;[6][5] other materials, such as steel, timber, and glass, are also featured.[7]
In the United Kingdom, brutalism was featured in the design of utilitarian, low-cost social housing influenced by socialist principles and soon spread to other regions around the world.[4][5][14] Brutalist designs became most commonly used in the design of institutional buildings, such as universities, libraries, courts, and city halls. The popularity of the movement began to decline in the late 1970s, with some associating the style with urban decay and totalitarianism.[5]
Looking at the one identified school which has had a collapse so far, Singlewell Primary in Kent, it looks like single-story brick buildings to my quick glance. Not Brutalist.
https://www.ablecanopies.co.uk/installations/singlewell-primary-school-second-installation/